<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

<div id="app">
    <h2>{{msg}}</h2>
    <h2 v-once> {{msg}}</h2>
</div>
<script src="../js/vue.js"></script>
<script>

    const app = new Vue({
        el: "#app",
        data: {
          msg: "hello"
        },
    })
</script>


</body>
</html>